1. Field of the Invention
The present invention relates to a shovel including a selective reduction catalyst system for reducing nitrogen oxide in exhaust gas of an engine using a reducing agent and a method for controlling such a shovel.
2. Description of the Related Art
A hybrid construction machine that stops driving a drive control system of an electric working element when an abnormality occurs in a motor generator or a drive control system of the motor generator is known.
However, conventional hybrid construction machines do not implement techniques for reducing the amount of nitrogen oxide in exhaust gas using a selective reduction catalyst system. Also, an appropriate process is not implemented upon detecting an abnormality in the selective reduction catalyst system. As such, conventional hybrid construction machines may not be able to fully comply with exhaust gas regulations. Also, when an abnormality occurs in the selective reduction catalyst system, drive operations of the drive control system of an electric working element are stopped.
In view of the above, a shovel is desired that includes a selective reduction catalyst system for reducing the amount of nitrogen oxide in exhaust gas and is capable of operating appropriately even when an abnormality occurs in the selective reduction catalyst system.